Middle Eastern Roast Lamb with Tahini Sauce

Inspired by Middle Eastern shawarma sandwiches, here we season leg of lamb with a flavorful spice paste spiked with garlic, cardamom, paprika and cumin and grill it over indirect heat to approximate the gentle cooking of a rotisserie. Serve the tahini sauce on the side—and be sure to keep any leftovers. They're great tucked into a pita pocket with shredded lettuce and diced tomatoes.